I was configuring my FC and had a nano-tech 1.3 45-90c battery plugged in to make sure everything was working. After around 5 minutes the battery died (got very low)? The only reason I noticed is that cleanflight stopped recognizing the input from the radio. I quickly unplugged it and checked its per cell voltage. All 3 cells were matching (withing .01 of each other) but below the recommended 3.x voltage. I charged it and after about 2 hours the charger gave an error message. I plugged the battery back into the voltage checker and the cells looked like the below. This freaked me out because i know it should only go to 11.1 for all and im wondering if its a battery issue or if it is a charger issue or something else. I am afraid to try any other batteries or do anything till I know what is happening. The other weird thing is that when the battery is plugged into the charger it shows a different v per cell when charging vs just in standby. Lastly if i unplug and replug in the battery to the V checker it sometimes shows nothing and other times shows the below numbers.

ALL-11.8
Cell1-3.74
Cell2-3.17
Cell3-4.2

The battery is not warm or puffed up....

It sounds like there's a dead cell in your battery.

Each cell, when fully charged, should register 4.2V for a total of 12.6V when fully charged. If the second cell really is reading 3.17V, that would explain why the battery only lasted five minutes.

(30-Apr-2017, 09:58 PM)unseen Wrote: It sounds like there's a dead cell in your battery.

Each cell, when fully charged, should register 4.2V for a total of 12.6V when fully charged. If the second cell really is reading 3.17V, that would explain why the battery only lasted five minutes.

Thank you for the response. I have requested an RMA for the battery. 

I do have a question though. Where are you getting the 4.2V and 12.6V full charged rating from? The battery itself says 3 Cell 11.1V on the sticker?

nominal voltage of a cell is 3.7 (you should never go below 3.3) fully charged cell (LiPo) is 4.2

there you have, amount of cells x nominal = sticker (11.1) in your case
amount of cells x fully charged = 12.6

you can lookup for 4s as well


as for the charging, i don't know what charger you use, if you have "Balance" program try it on the battery.

- how to check the V in your batt/cells,
1. get a multimeter
2. power it on
3. set to DC 20v
4. connect ground to ground battery, positive to positive battery
5. read whole pack voltage.

now move to the balancer plug (the white one usually).
connect probes to it and you will see either 3.7 or moving higher you can see up to full voltage, this way you can easy identify which cell is dead

(30-Apr-2017, 11:54 PM)Grisha0 Wrote: nominal voltage of a cell is 3.7 (you should never go below 3.3) fully charged cell (LiPo) is 4.2

there you have, amount of cells x nominal = sticker (11.1) in your case
amount of cells x fully charged = 12.6

you can lookup for 4s as well


as for the charging, i don't know what charger you use, if you have "Balance" program try it on the battery.

- how to check the V in your batt/cells,
1. get a multimeter
2. power it on
3. set to DC 20v
4. connect ground to ground battery, positive to positive battery
5. read whole pack voltage.

now move to the balancer plug (the white one usually).
connect probes to it and you will see either 3.7 or moving higher you can see up to full voltage, this way you can easy identify which cell is dead

Awesome info thank you.

(Ground and Postive)ALL - 7.69
(blue) Red - 2.76
(white) Blue - 2.41
(black) White - 2.52

While those all add up and make sense the weird thing is that when plugged into charger is shows totally different numbers for this battery.
That would lead me to believe that the charger is freaking out but then I tested all other batteries the same way but they all match within .01 of what the charger shows vs the mutlimeeter....

if you slightly move the balance connector up and down while plugged into charger, does cell voltage variate?

What charger?